Atomic Number
33
Element 33
Arsenic (As)
Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal.
Atomic Mass
74.922 u
Category
Metalloid
Period
4
Group
Group 15: nitrogen group
Phase
solid
Density
5.727 g/cm3
Electron Shells
2, 8, 18, 5
Atomic Structure
Protons: 33. Electrons: 33. Neutrons: Varies by isotope.
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p³
Why Arsenic Matters
Arsenic helps connect atomic number 33, metalloid behavior, period 4 trends, and electron shell structure. Its solid phase, atomic mass of 74.922 u, and electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p³ make it useful for comparing bonding patterns across the periodic table.
Discovery and Occurrence
Arsenic was discovered Unknown. Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal.
Safety and Handling Context
Arsenic is presented here for learning and comparison. Pure elements and laboratory compounds can have hazards that depend on dose, form, and setting.
Related Elements
Frequently Asked Questions
- What is the atomic number of Arsenic?
- Arsenic has atomic number 33, which means a neutral atom has 33 protons and 33 electrons.
- What is the chemical symbol for Arsenic?
- The chemical symbol for Arsenic is As.
- What category is Arsenic in?
- Arsenic is classified as a metalloid and sits in period 4 of the periodic table.
Explore Arsenic in 3D
Use the interactive table above to rotate atomic models, compare periodic trends, and move from Arsenic to neighboring elements without losing your place.